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Cleaning device for downhole tools

a technology for cleaning devices and tools, which is applied in the direction of cleaning apparatus, fluid removal, application, etc., can solve the problems of wear to the device and/or the internal diameter of the casing, friction may occur at the interface of rotating (drill string) and non-rotating, and the attached device cannot be rotated with the drill string

Inactive Publication Date: 2010-11-23
WEATHERFORD SWITZERLAND TRADING & DEV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The solution effectively reduces friction and prevents welding between the drill string and scraper blades, allowing for higher drilling speeds without wear or damage, thereby reducing maintenance costs and improving drilling efficiency.

Problems solved by technology

When rotating the drill string, it is often undesirable for the attached device to be rotated with the drill string.
Rotation of the device relative to the casing may therefore result in wear to the device and / or to the internal diameter of the casing.
However, one disadvantage inherent in the scraper tool being rotatably mounted relative to the drill string is that, upon rotation of the drill string, friction may occur at the interface of rotating (drill string) and non-rotating (cylindrical body) parts.
This friction can result in damage to the device or downhole tool.
Friction occurs between surface asperities, which causes heat, and the asperities may weld together.
Further rotational displacement of one part relative to another causes these micro-welds to break, which makes the interface surface even rougher, resulting in greater friction between the parts.
In extreme cases, such as at excessive speeds of rotation, the heat generated by the friction during rotation may cause the rotating and non-rotating parts to weld together at a macro level.
Although steel typically has a melting temperature of over 1500° C., galling can occur at much lower temperatures, such as 800° C. The fusing of parts necessitates the carrying out of repairs and / or the replacement of the tool, which is expensive and time-consuming.

Method used

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  • Cleaning device for downhole tools
  • Cleaning device for downhole tools
  • Cleaning device for downhole tools

Examples

Experimental program
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Effect test

first embodiment

[0058]FIG. 1 shows a downhole tool 1 within a casing 10 comprising a string 5 on which is provided a cleaning device in the form of a scraper tool 30. In this embodiment, the device 30 includes a cylindrical sleeve 32 mountable to the drill string 5.

second embodiment

[0059]FIG. 2 shows a device, also in the form of a scraper tool 3, within a casing 10 comprising a base member or cylindrical body 20 on which is provided a scraper blade assembly 40. In this embodiment, the cylindrical body 20 forms a longitudinal component of the drill string. The cylindrical body 20 is provided with connecting means in the form of threaded connectors 22, 24 for connection to adjacent drill pipes or adjacent downhole tools forming the drill string.

[0060]Referring first of all to both FIGS. 1 and 2, the casing 10 is comprised of a number of longitudinal sections (not shown) which are connected together so that the casing 10 may be vertically inserted into a borehole (not shown). The casing 10 therefore has an upper end 12 and a lower end 14. The casing 10 is typically set in the borehole by cementing the space between the borehole and the casing. However, the cementing process may leave cement deposits within the casing 10 and at the bottom of the borehole. It is d...

third embodiment

[0065]FIGS. 3 to 6 show the invention. The scraper device 50 is connected to a downhole tool 5 for use within a well bore. The device 50 comprises three rings or sleeves 60 arranged sequentially and axially along a base member 52 which is non-rotatably mounted to the downhole tool 5. The three sleeves 60 are rotatably mounted around the base member 52 but are non-movable relative to each other as they are fixedly connected using locking dogs 61.

[0066]Each sleeve 60 has a support member 62 and four protruding members or blades 64 which protrudes from the support member 62 and which, in use, contact the inner surface of the well bore. The blades 64 also provide inhibiting means to inhibit rotation of the sleeve 60 relative to the downhole tool 5. Adjacent sleeves 60 are arranged such that their blades 64 are circumferentially offset from each other. Each blade 64 is provided with a downwardly orientated cutting blade and the upper edge of each blade 64 is tapered away from the casing ...

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Abstract

A cleaning device connectable to a downhole tool for use within a well bore, the cleaning device comprising: a base member non-rotatably mountable to the downhole tool; and at least one sleeve member rotatably mountable to and around the base member, the sleeve member having a support member and at least one protruding member which protrudes from the support member and which, in use, contacts an inner surface of the well bore, wherein the support member comprises a bearing material.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to cleaning devices for downhole tools. In particular, but not exclusively, the invention relates to scraper devices having an improved bearing arrangement, the scraper devices being connectable within a drill string.[0003]2. Brief Discussion of the Related Art[0004]During oil and gas exploration and extraction, a drill string is rotated to form a well bore. The bore is often lined using a casing which generally comprises a number of steel pipes that are connected together as they are run into the bore. A number of different devices may be attached within the drill string, such as cleaning tools, collecting tools and impellers.[0005]When rotating the drill string, it is often undesirable for the attached device to be rotated with the drill string. In some cases, the device may be in contact with the internal diameter of the casing. Rotation of the device relative to the casing may therefore...

Claims

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Application Information

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Patent Type & Authority Patents(United States)
IPC IPC(8): E21B37/02E21B37/00
CPCE21B37/02Y10T29/49826E21B37/00
Inventor BOOTH, RICHARD KEITH
Owner WEATHERFORD SWITZERLAND TRADING & DEV